This PAS establishes a unique INPUT INTERFACE for connection of an EXTERNAL ALARMING DEVICE to HAEMODIALYSIS EQUIPMENT. The INPUT INTERFACE of the HAEMODIALYSIS EQUIPMENT is designed as a simple solution@ which takes a SINGLE FAULT CONDITION of the INPUT INTERFACE into account@ to stop the extracorporeal blood flow in case of needles slipping out from the fistula or graft detected by the EXTERNAL ALARMING DEVICE.